Image reading device and image reading method

Abstract

An image reading device which reads a document as an image includes a light source unit, a light receiving unit, a transporting mechanism which relatively transports either one of the light receiving unit or the document, a light reception control unit, andan irradiation control unit which irradiates the light receiving unit with the light from the document during a first light receiving period starting from a beginning point of the charging period and a second light receiving period ending at an ending point of the charging period and which does not irradiate the light receiving unit with the light from the document between the first light receiving period and the second light receiving period.

Description

[0001]The entire disclosure of Japanese Patent Application No. 2007-227514, filed Sep. 3, 2007 is expressly incorporated by reference herein.BACKGROUND[0002]1. Technical Field[0003]The present invention relates to an image reading device and an image reading method.[0004]2. Related Art[0005]JP-A-1994-178059 disclose an image reading device which reads a document as an image in a manner such that light is emitted from a light source unit having a light source to a document, and reflected light which is light reflected from the document or transmitted light which is light transmitted through the document is inputted in an image sensor. As a light source of the light source unit of the image reading device, a technique using a light emitting diode (LED) is known (for example U.S. Pat. No. 5,767,979).[0006]Generally, an image reading device reads an image by repeatedly performing a series of processes, such as accumulating charges in light receiving elements of an image sensor while tra...

AI Technical Summary

Benefits of technology

The invention provides a technique for improving the quality of an image that is read. An image reading device is provided that includes a light source, a light receiving unit, a transporting mechanism, a light reception control unit, and an irradiation control unit. The device controls the light source to irradiate the light receiving unit with light at different times during the reading process. This technique helps to equalize the average transporting speed of the light receiving unit and suppress any deterioration of the image quality, even if the transporting speed changes. The method can be implemented using computer programs or recording media.

Problems solved by technology

However, the known technique does not mention the relative transporting speed of the image sensor to the document.

Accordingly, if the relative transporting speed of the image sensor to the document changes in the middle of image processing, image quality of the read image is likely to be deteriorated.

This problem does not occur only in the case of using the LED as a light source but also commonly arises when using different light sources, such as a fluorescent lamp.

Images